IAG provides arabinogalactans, derived from larch. Arabinogalactans are long, densely branched, high-molecular-weight polysaccharides that act as natural activators of the immune system's complement pathway. The complement pathway is responsible for nonspecific host defense mechanisms. Studies have also documented arabinogalactan's ability to enhance the cytotoxicity of natural killer cells. In addition to immune support, IAG is also considered a prebiotic, as it is able to support the growth of friendly bacteria.